Control system for clothes dryers



Oct. 1, 1957 R. L. DUNKELMAN CONTROL SYSTEM FOR CLOTHES DRYERS 2Sheets-Sheet 1 Filed March 8, 1956 HIGH H AT CON ROLLED m K m R P s ETART HEAT HIS ATTORNEY Oct. 1, 1957 R. L. DUNKELMAN CONTROL SYSTEM FORCLOTHES DRYERS 2 Sheets-Sheet 2 Filed March 8, 1956 N WF m@ ON I. j

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ROBERT L. DUNKELMAN HIS ATTORNEY United States Patent CONTROL SYSTEM FORCLOTHES DRYERS Robert L. Dunkelman, Shreveport, La.,

assignor to General Electric Company,

My invention relates to clothes dryers and more particularly to theelectrical control systems used in such dryers.

It is an object of my invention to provide a new and improved controlsystem for clothes dryers.

It is another object of my invention to provide a control system forclothes dryers, whereby a dryer may be selectively operated to produce aplurality of different clothes treating operations including a high heatclothes drying operation wherein the heater of the dryer is energizedcontinuously, and a controlled heat clothes drying operation where inthe heater is cycled by a thermostat.

A further object of my invention is to provide a clothes dryer controlsystem, whereby a dryer may be selectively operated to produce threedifferent clothes treating operations comprising respectively acontrolled heat clothes drying operation, a high heat clothes dryingoperation, and a clothes tumbling operation without heat.

Another object of my invention is to provide a clothes dryer controlcircuit of this latter type including thermostatic means forautomatically terminating either of the clothes drying operations whenthe clothes have substantially dried.

Still another object of my invention is to provide a clothes dryercontrol system effective to produce the three operations, in which thedrive motor and heater circuits are closed through the contacts of arelay which is dropped out automatically by thermostatic means in thetwo drying operations when the clothes have completed drying.

A still further object of my invention is to provide a clothes dryercontrol circuit in which the drive motor and heater circuits are closedthrough the contacts of a thermostatically closed relay and in which theopening of the dryer door interrupts the two circuits but does not causedropping out of the relay, whereby both circuits are again renderedoperative when the door is reclosed.

My invention also has as its object the provision of a clothes dryercontrol system including a relay having contacts in the drive motor andheater circuits, which is energized by means of a remotely located pushbutton to initiate the dryer operation and which is de-ener gized bythermostatic means to terminate dryer operation when the clothes havedried.

In carrying out my invention I provide a clothes dryer having suitableclothes tumbling means. A drive motor is provided for driving theclothes tumbling means and a heater is arranged for heating the clothesbeing tumbled. By my invention the drive motor and the heater arecontrolled by means of a novel control system which includes a timermechanism and a heater cycling thermostat. This control system providesfor three different operations of the dryer comprising respectively ahigh heat clothes drying operation wherein the heater is energizedcontinuously, a controlled heat clothes drying operation wherein theheater is cycled by a thermostat, and a clothes tumbling operationwithout heat wherein the heater is de-energized at all times.

in the system the drive motor and the heater are both energized bycircuits through switches of the timer mechanism. In addition to itstimer switch, the heater circuit also includes the cycling thermostatand a normally closed manually operated heater switch. Further, theheater circuit includes a normally open manually operated shunt switchconnected in parallel with the contacts of the thermostat. The drivemotor is energized in all three opera; tions of the dryer, and thedifferent operations are effected by means of the manually operatedswitches in the heater circuit. To produce the controlled heat clothesdrying operation both switches are left in their normal positionswhereby the heater is cycled by the thermostat during the dryingoperation. Alternatively, to provide the high heat operation, the shuntswitch around the thermostat is closed and thereby the heater isenergized continuously. The clothes tumbling operation without heat iseffected by opening the heater switch whereby the heater is completelyde-energized. The manually operated switches are preferably controlledby push buttons whereby move ment of either of the switches from itsnormal position returns the other of the switches to its normalposition.

In my preferred system there is also included a relay having contacts inboth the drive motor circuit and the heater circuit, and a secondthermostat responsive to the exhaust air leaving the tumbling means forcontrolling the relay. To initiate the dryer operation a push button isoperated which is effective to energize the relay coil and .therebyclose both circuits. The exhaust air thermostat is effective tode-energize the relay coil when the clothes have dried, and therebyterminate the dryer operation no matter what the position of the timermechanism. For safety purposes this preferred control system alsoincludes means whereby both the motor circuit and the heater circuit arede-energized whenever the dryer door is opened, but the relay coil is soarranged that it remains energized even when the door is opened. Therebythe motor and heater circuits are both returned to operation automatically when the door is reclosed.

The features of my invention which I believe to be novel are set forthwith particularity in the appended claims. The invention itself,however, both as to its organization and method of operation may be bestunderstood by reference to the following description taken inconjunction with the accompanying drawings in which:

Fig. 1 is a perspective view of a domestic clothes dryer including acontrol system embodying my invention, the view being partially brokenaway in order to show details;

Fig. 2 is a fragmentary view showing the operator controls of thecontrol system; and

Fig. 3 is a schematic diagram of the control system itself.

Referring now to Fig. 1 I have shown therein a clothes dryer 1 which isillustrative of the various clothes dryers in which my new and improvedcontrol system may be used. The dryer 1 includes a rotatable drum orbasket 2 which is mounted for rotation about a generally horizontalaxis. The basket 2 is disposed within an outer enclosing cabinetstructure 3 and aligned openings 4 and 5 are provided respectively inthe front walls of the basket and the cabinet structure for the loadingand unloading of clothes from the basket. The openings 4 and 5 areflanged as shown to prevent clothes from dropping down between thebasket and the cabinet. A door 6 hingedly mounted on the cabinet closesthe opening 5 during operation of the dryer.

For rotating the basket 2 during operation of the dryer there isprovided an electric motor 7 which is connected to the basket by asuitable belt drive 8. The pulleys (not shown) mounting the belt driveare so arranged that the basket 2 'is driven at a suitable speed fortumbling articles of clothing placed therein. The basket '2 preferablyincludes upstanding ribs on the inner surface thereof to aid inproducing the tumbling action. Besides driving the basket 2, the motor 7also serves to drive air moving means for circulating a stream of airthrough the basket during the operation of the machine. The air movingmeans comprises a centrifugal blower 9 which is driven by motor 7 bymeans of a direct coupling 10. The blower 9 draws in air from thesurrounding room through a conduit 11 which leads from a screened airinlet opening 12 in the toe board 13 of the cabinet.

The air drawn in by the blower 9 is discharged through an opening 14 atthe top thereof into a space 15 which is separated from the rotatingbasket 2 by a battle 16. As shown, the baffle 16 extends upwardly fromthe base of the machine to a point in the general vicinity of anelectrical heating element 17 mounted at the top of the machine, thebafiie 16 being curved arcuately around the perforated side wall 18 ofthe basket for a portion of its length. The air discharged from theblower 9 flows upwardly through the space 15 and passes outwardly therefrom across the electrical heating element 17. The air still underpressure from the blower then flows downwardly through the formaminatedcylindrical wall 18 of the basket. A generally arcuate bafile orwrap-around 19 confines the flow path of the air so that it ispositively passed through the wall 18 into the basket. The air movesdownwardly through the basket and the articles of clothing being tumbledtherein and next passes into a collecting chamber 20 lying beneath thebasket 2 on the opposite side of the baflie 16 from the space 15. Fromthe chamber 20 the air is discharged out of the cabinet into thesurrounding room through an appropriate lint trap structure 21 mountedin the toe board 13.

The machine 1 is intended for use both as a clothes drying means and asa clothes sprinkling means. When the machine is to be used as a clothesdryer the heater 17 is energized along with the drive motor 7. Thus theair discharged from space 15 absorbs heat from the heater 17 as itpasses thereover. The heated air then extracts moisture from the clothesbeing tumbled in the drum as it passes therethrough. The heatingelement, however, is not energized when the machine is being used as aclothes sprinkling means. Thus the air passing through the drum is notheated and it does not extract moisture from the clothes. Any suitablemeans may be used to sprinkle the clothes during this operation, but itis preferred to use a container which can be mounted on the drum 2 so asto discharge water onto the clothes at a slow rate as the basketrotates. A suitable container for this purpose is shown and described inthe copending application of Eugene G. Olthuis, S. N. 430,794, filed May19, 1954, and assigned to the same assignee as the present invention. Itwill be understood, of course, that if the sprinkling means are notmounted within the drum, this clothes tumbling operation of the dryerwithout heat may be used for flufling previously dried clothes or forany other purpose wherein it is desired to tumble clothes without theapplication of heat.

Referring now to Fig. 3 I have shown therein a control system for thedryer 1, which embodies my invention in one preferred form thereof. Thiscontrol system provides forthree different types of clothes treatingoperations to be carried out within the dryer. It provides for a highheat clothes drying operation wherein the heater 17 is energizedcontinuously so long as the drying operation continues. It also providesfor a controlled heat operation wherein the heating element 17 is cycledon and off by a cycling thermostat so that the temperature of the inletair entering the drum 2 never rises above a predetermined temperature.Further, it provides for a clothes tumbling operation without heatwherein the heater 17 is not energized at any time. 1 In order to timethe length of the clothes tumbling or sprinkling operation and also inorder to provide timed clothes drying operations of both of the abovementioned types, i. e., the high heat type and the controlled heat type,the control system includes a timer mechanism 22. The timer mechanismcomprises a timer motor 23 and a pair of cams 24 and 25 which are drivenby the timer motor through suitable one-way clutch means. The cams 24and 25 operate switches 26 and 27 respectively through suitable camfollowers which ride on their peripheries. The two switches 26 and 27are connected respectively in the circuits for energizing the drivemotor 7 and the heater 17, the switch 26 being connected serially in theheater circuit and the switch 27 being connected serially in the drivemotor circuit. Both the drive motor and the heater circuits and theconnection of the switches 26 and 27 in these circuits will be morefully described hereinafter. in order that the switch operating earns 24and 25 may be adjusted to any desired position, the timer mechanism isprovided with a rotatable dial 28 which is mounted on the same shaft asthe cams. By adjusting the dial 23 and thus the earns 24 and 25, thetimer may be set to operate for various periods of time before openingswitches 26 and 2'7 and breaking the heater and drive motor circuits.The timer mechanism may be mounted at any suitable point within themachine but preferably is mounted on the back: splasher 29 thereof as isshown in Fig. 1.

Besides the timer mechanism 22 the control system also includesthermostatic means for determining the length of the machine operation.These thermostatic means are operative during both the high heat clothesdrying operation and the controlled heat clothes drying operation toterminate the operation of the machine whenever the clothes have dried.No matter what the original setting of the timer may be, thesethermostatic means will shut off the dryer as soon as the clothes havecompletely dried. Thus no matter how mistaken the operator may be in hersetting of the dial 28, it is impossible for the clothes to be scorchedor otherwise heat damaged.

The thermostatic means for terminating the clothes drying operationscomprise two thermostats 30 and 31 which are responsive to thetemperature of the exhaust air leaving the rotating drum 2. Thesethermostats may be positioned within the exhaust air collecting chamber20 in any suitable manner so as to sense the exhaust air temperature.For example, a bracket 30a for mounting the thermostat 30 is shown inFig. 1. The exhaust air temperature closely follows the temperature ofthe clothes being tumbled and thereby the thermostats 30 and 31 inetfect respond to the clothing temperature.

During the clothes drying operation, the temperature of the clothes andthus the exhaust air temperature rise slowly as the drying operationprogresses. For a period of the operation a plateau may even occur inthis temperature rise where the amount of heat utilized in moistureextraction is approximately equal to that supplied from the heater 17.However, when the clothes have substantially dried, the clothingtemperature and the exhaust air temperature then begin to rise abruptly.The purpose of the thermostat 30 is to open the heater circuit andthereby de-energize the heater 17 when the clothes have substantiallydried. The thermostat 30 is thus arranged so that it remains normallyclosed during the slow rise in the exhaust air temperature accompanyingthe drying process. In other words it is set so that it does not open atthe temperatures through which the slow rise occurs. It is set howeverto open at a temperature slightly above that at which the abrupt risedoes occur. In this manner the thermostat 30 remains closed so long asthe drying process continues but opens as soon as the clothes havedried. The means whereby the thermostat 30 opens the heater circuit onceit opens itself are described hereinafter.

The other exhaust air thermostat 31 is utilized to provide a cool-downperiod for the machine after the heater 17 has been turned off by thethermostat 30. In other words the thermostat 31 maintains the drivemotor 7 running after the heater has been turned off to continue inoperation the tumbling drum and the blower 9. This continued operationof the tumbling drum and the blower results in the clothes being tumbledwith air at room temperature being blown through them. The clothes arethus cooled down to a suitable temperature for removing them from themachine. When this temperature is reached the thermostat 31 opens themotor circuit and terminates the operation of the dryer completely. Thecircuit whereby the thermostat 31 accomplishes this result is explainedhereinafter. To eifect this result the thermostat 31 is calibrated sothat it is normally open at room temperature, but is closed at anytemperatures above those suitable for removing the clothes from thedrum. Thus during the dryer operation the thermostat 31 is open when thedryer is first placed in operation. However it closes as the machineheats up during the drying operation and does not again re-open untilthe point in the cool-down period is reached where the temperature issuitable for the removal of the clothes.

In order to provide means whereby the heater circuit may be openedbefore the motor circuit, the control system is provided with a relay32. This relay includes a coil 33 and an armature 34 which is operatedby the coil. It further includes three sets of contacts or switches 35,36, and 37 which are operated by means of the armature. All of thesesets of contacts or switches are closed whenever the armature is raisedby the coil 33, and all are opened whenever the coil is de-energized toallow the armature to drop out. It will be noted incidentally that theswitches 36 and 37 share a common contact or switch arm. The switch 35is connected serially in the energizing circuit for the heater 17 andthe switches 36 and 37 are connected in series in the energizing circuitfor the drive motor 7. Thus whenever these switches are opened, both theheater and the drive motor circuits are broken at those points.

During the operation of the machine the coil 33 of the relay is normallyenergized by means of the thermostat 30. Thus the switches 35, 36 and 37are held closed until the clothes have substantially dried. At thatpoint, however, the thermostat opens and tie-energizes the coil 33allowing the relay to drop out. This de-energizes the heater circuit bymeans of the switch and also of course opens the drive motor circuit.However the overrun thermostat 31 provides a parallel path around theswitches 36 and 37 to keep the drive motor energized during thecool-down period. Both the heater circuit, the drive motor circuit andthe circuit for energizing the relay coil 33 are described hereinafter.

In order to produce selectively the two types of clothes dryingoperations and the clothes tumbling operation without heat, two manuallyoperated switches 38 and 39 and a heater cycling thermostat 40 areprovided in the heater circuit. The switch 38 is a normally closedswitch, and it and the thermostat 40 are connected in series circuitrelation in the heater circuit with the heater itself. The switch 39however is a normally open switch and rather than being connected inseries circuit relation it is connected in parallel with the contacts ofthe thermostat 40. In other words it forms a normally open shunt aroundthe thermostat 40.

The purpose of the switch 38 is to de-energize the heater 17 during theoperation of the dryer, thereby to produce the clothes tumbling orsprinkling operation without heat. Conversely, the purpose of the switch39 is to maintain the heater energized continuously during the operationof the machine to obtain the high heat drying operation. The thermostat40 is included for controlling the heater to produce the controlled heatclothes drying operation of the machine. Specifically, when thethermostat 40 is placed in operation, it is intended to control theheater 17 so as to maintain the inlet air to the drum at a temperaturesafe for all types of fabrics. It does this by cycling the. heater onand 01? in response to the inlet air temperature. The thermostat 40 maybe positioned at any suitable place to sense the inlet air temperaturebut 6 preferably is mounted near the top of the battle 19 as shown.

The three different types of clothes treating operations are produced asfollows. If it is desired to effect a clothes tumbling or sprinklingoperation without heat, the switch 32% is opened. This breaks the motorcircuit and prevents the heater from being energized at any time. If itis desired to produce the controlled heat operation, the switch 38 isclosed and the switch 39 is left open. This places the heater under thecontrol of the cycling thermostat as whereby the heater is cycled on and01f to keep the inlet air to the drum at a temperature safe for thesheerest fabrics and synthetics. If it is desired to have the high heatoperation of the dryer, then both the switches 38 and 39 are closed. Theclosing of the switch 39 shorts out the thermostat whereby the heater isenergized continuously until either the exhaust thermostat 30 opens orthe timer mechanism times the machine out.

In my preferred embodiment the heater control switch 38 and thethermostat shunt switch 39 are operated by means of a plurality of pushbuttons 41, 42 and 43. The push buttons are all mounted within a housing44, which housing also serves to mount the switches 38 and 39. Each ofthe push buttons is provided with an inwardly extending switch actuatingarm 45, 45a and 4511 respectively, and each of these operating rods isprovided with two laterally extending tabs thereon. One of the tabs isprovided adjacent the center of the rod as indicated at 46, 46a and 46brespectively, and the other of the tabs is formed at the end of the redas shown at 47, 47a and 47b respectively. The tabs 47 and 47a on therods 45 and 45a of buttons 41 and 42 engage respectively one of the armsof the switches 38 and 39. Specifically, if the button 41 is pushedinwardly tab 47 engages the right-hand arm of the switch 38 so as toopen switch 38. Conversely if the button 42 is pushed inwardly, tab 47aengages the left hand arm of the switch 39 so as to close switch 39. Thepush button 43 does not operate a switch when pushed inwardly, butrather is used to return both the buttons 41 and 42 to their normal oroutward position.

The push buttons 41, 42 and 43 are so arranged that whenever any of themis pushed inwardly, the other two are automatically returned to theiroutward positions. This automatic return action is effected by means ofthe center tabs 46, 46a and 46b on the operating rods 45, 45a and 455.These tabs engage respectively upstanding lugs 48, 48a and 48b providedon a movable latch rod 49 whenever they are moved inwardly. The oppositeends of the latch rod 49 are mounted in aligned apertures 50 in the sidewalls of the casing 44 so that the rod is axially movable within thecasing, and the rod is spring biased to the right (as viewed in Fig. 3)by means of a spring 51. As shown, each of the lugs on the latch rodincludes an inclined surface, as indicated at 52, 52a and 52b, andfurther includes a recess disposed below the lower point of the inclinedsurface as indicated at 53, 53a, and 53b. As any of the push buttons aremoved inwardly the center tab 46, 46a or 4612 thereof strikes theinclined surface of its associated lug 48, 48a or 43!) and moves thelatch rod 49 to the left. This movement of the latch rod to the leftreleases the center tab of whatever push button was previously depressedand that push button is thereby returned to its normal or outwardposition by the action of a return spring which is disposed between itand a cross piece mounted on the housing. The return springs are shownat 54, 54a and 54b respectively. Once the center tab on the button beingpushed passes the point of the inclined portion of the lug, however, thelatch rod springs back to the right and the appropriate recess 53, 53aor 53b engages the tab to maintain that push button down.

To explain this action a little more fully, in the position of thecontrol illustrated the. push button 43 is depressed downwardly and heldin that position by the engagement of the latch rod lug 48b with the tab46b. Now assume that the button 41 is pushed inwardly. As a result ofthe movement of the button 41, the latch rod will be moved to the leftby the tab 46 thereby freeing the tab 46b. The button 43 will,therefore, move outwardly under the action of the spring 54b and returnto its normal position. However, as soon as the tab 46 of the button 41passes the right hand point of the inclined surface 52 on lug 48, thelatch rod will spring back and hold the button 41 inwardly. The tab 4-6will be caught in recess 53 whereby the button can not move outwardly.The same result will be effected no matter which of the button is pushedinwardly. The button pushed inwardly will be held in the depressedposition while all the other buttons will be released and automaticallyreturned to their outward or normal positions.

Besides the push buttons 41, 42 and 43 the control also includes oneadditional push button 55. This push button 55 is mounted on thebacksplasher 29 adjacent the other push buttons and comprises a startbutton for initiating the operation of the machine. It controls a switch56 which is connected in the holding circuit for relay coil 33 asexplained below.

To explain in detail the operation of my new and improved control systemand also the various electrical connections contained therein, let it beassumed that it is desired to effect a controlled heat clothes dryingoperation within the dryer ll. Further, let it be assumed that it isdesired to have the dryer turned off automatically when the clothes aredried, rather than to have the dryer set to run for a predeterminedlength of time. To condition the dryer for this operation the pushbutton 43 is depressed and the dial 28 is moved into the section markeddry on the dial. The depressing of button 43 causes switches 38 and 39to assume their normal positions for energizing the heater through thethermostat 40, and the setting of the dial 28 conditions the timermechanism for placing the machine in operation. Specifically, thesetting of the timer rotates the leading edges of the raised portions ofthe cams under the cam followers of switches 26 and 27. This closes theswitches 26 and 27, and since the dry portion of the dial 28 isimmediately adjacent the off sector, the timer is set to run for themaximum possible time before it will open the switches 4 26 and 27.

With the dial set in the dry position and the push button 43 depressed,the operation of the machine is initiated by depressing the start button55. This closes the start switch 56 and closes a circuit for energizingthe coil 33 of the relay 32. All the electrical components of the dryerand the control system are energized from a three-wire power sourcecomprising supply conductors 57 and 58 and a neutral line 59, and theclosing of the start button energizes the coil 33 between the neutralline and the conductor 58. In my preferred circuit for domestic use itis contemplated that there will be a voltage of 220 volts between thesupply conductors 57 and 58 and a voltage of 110 volts between theneutral conductor 59 and each of the supply conductors, and thus whenthe switch 56 is closed, the relay coil 33 is energized across 110volts.

Starting with the neutral conductor 59 the relay coil circuit closed bythe start switch extends through a fusible link 60 and a conductor 61 tothe closed switch 27 of the timer mechanism. From the switch 27 thecircuit proceeds through a conductor 62, the start switch 56 itself andconductors 64 and 65 to one side of the relay coil 33. The circuit iscompleted from the relay coil through conductors 66, 67 and 63 to thesupply conductor 58. With the relay coil 33 energized by this circuitthrough the start switch, the armature 34 is lifted upwardly closing theswitches 35, 36, and 37 with the switches 36 and 37 being connectedtogether through their common contact.

One result of the closing of the various switches of the relay is thatthe relay coil itself is locked in so that the start button 56 may bereleased. Specifically, the relay coil is locked in by a circuit throughthe switch 36 and the exhaust thermostat 36. Starting with the conductor62 which is, of course, connected to the neutral line 59 by the timerswitch 27, the holding circuit for the relay extends through a conductor69, the switch 36, a conductor 70, the closed thermostat and a conductor71 to the conductor connected to the one side of the relay coil. Therelay circuit is completed from the other side of the coil as beforethrough the conductors 66, 67 and 68 to the supply conductor 58. Withthis circuit completed by the closing of the switch 36, it will be seenthat the relay is locked in until such time as the. exhaust thermostat30 is opened by the temperature of the exhaust air. The thermostat 30is, of course, not open until such time as the clothes are dried, itopening only at an exhaust air temperature which indicates that theclothes have reached that condition.

The closing of the relay 32 also results in circuits being completed forthe heater l7 and the drive motor 7. Specifically, the drive motor isenergized by a circuit across the neutral line 59 and the conductor 58.Commencing with the neutral line 5? the motor circuit ex-v tends throughfusible link 60, conductor 61, timer operated switch 27, and conductors62 and 69 to the switch 36. It then passes through the relay switches 36and 37 in series and proceeds through. conductors 72 and 73 to a switch,74 which is controlled by the door 6. The switch 74 is so arranged withregard to the door 6 that it connects the conductor 73 to one contact 75when the door is closed, whereas when the door is open it connects theconductor 73 to a second or back contact 76. Assuming the door of themachine to be closed the motor circuit extends through the switch armand the contact 75 to a conductor 77, and from the conductor 77 itpasses through another conductor 78 to the start and run windings 79 and88 of the motor 7. From the windings 7 9 and 80 the motor circuit iscompleted through the conductor 68 to the suppiy conductor 58. As shown,the run winding 80 is connected directly to the conductor 68. The startwinding is, however, connected thereto through the contacts 81 of amotor centrifugal switch 82 and the conductors 83 and 67. Thecentrifugal switch 82 is operated by the motor 7, and it is so arrangedthat the contacts 81 are closed whenever the motor is at rest but areopened as soon as the motor comes up to speed. Thus the start winding 79is connected in the circuit only until the motor comes up to speed. itis then removed from the circuit by the centrifugal switch and the motorcontinues to run under the action of the main winding 86 alone. With themotor energized through this circuit, it will be seen that it willcontinue to operate until such time as either the timer operated switch27, the door switch 74 or the relay 32 is opened.

The heater circuit completed by the closing of the relay 33 is energizedacross the supply conductors 57 and 53 so that the heater 17 isenergized by the full 220 volts available in the supply. Commencing withthe supply conductor 57, the two resistors 34 and 85 of the heatingelement are directly connected to that conductor. From the other side ofthe resistors, the heater circuit extends through a line 86 to theswitch 38. Since the push button 43 is operated inwardly to obtain thedesired controlled heat operation, the push button 41 is in its outer ornormal position whereby the switch 38 is closed. From the switch 38 theheater circuit then passes through a conductor 87 to the thermostat 40,and from the thermostat it extends through conductors 88 and 89 to theswitch 26 of the sequence control. Since the heater shunting switch 39is not closed but rather remains open when the button 43 is depressed,the thermostat is connected serially in the heater circuit and willbreak the circuit whenever it opens. From the switch 26 the heatercircuit continues through a conductor 90 to the switch 35 of the relayand thence passes through a line 91 to a set of back contacts 92 of themotor centrifugal switch 82. These contacts 2 are open when the motor isat rest but are closed whenever the motor comes up to speed. Assumingcontacts 92 to be closed, the heater circuit is then completed throughthe conductors 83, 67 and 68 to the supply conductor 58.

Energized through this circuit it will be seen that the heater 17 willremain energized under the control of the cycling thermostat 40 so longas the timer operated switch 26, the relay switch 35 and the centrifugalswitch contacts 92 remain closed. The opening of any of these switchesor contacts will, however, interrupt the heater circuit and de-energizethe heater. Due to the action of the thermostat 40, the heater isenergized intermittently so as to keep the temperature of the inlet airto the-drum below the temperature which might result in harm to sheerfabrics and synthetics. For example, it is contemplated in oneembodiment of my invention that the inlet air temperature will not beallowed to rise above 170 F. as a result of the action of the cyclingthermostat 40.

Besides the drive motor circuit, the heater circuit and the relayholding circuit, one additional circuit is energized by the closing ofthe relay 33; and that additional circuit is a circuit for energizingthe timer motor 23. The timer motor 23 is specifically energized by acircuit across the neutral line 59 and the conductor 58. Starting withthe neutral line 59 the timer motor circuit extends through neutral link60, conductor 61, timer operated switch 27, conductors 62 and 69, relayswitches 36 and 37 in series, and conductors 72 and 73 to the doorswitch 74. From there the timer motor circuit continues throughconductors 77 and 93 to the timer motor itself and is completed from thetimer motor through conductors 94 and 63 to the supply conductor 59.

Energized through this circuit it will be seen that the timer motor willcontinue in operation until such time as either the relay switches orthe door switch is opened. Opening of either of these elements willinterrupt or terminate the timer motor operation. So long as the timermotor is energized it drives the cams 24 and 25 toward the off position,that is, the illustrated position, wherein the recesses in the cams 24and 25 move under their respective followers to open the switches 26 and27.

With the components of the control system and the dryer energized inthis manner, the dryer continues in op eration to extract moisture fromthe clothes until one of two things happens, either the timer mechanismopens the switches 26 and 27 or the thermostat 30 opens the relayholding circuit. The timer opens the switches 26 and 27 after apredetermined length of time and the thermostat 30 opens the relayholding circuit when the dryer exhaust temperature indicates that theclothes have dried. If the switches 26 and 27 are opened, all of thecircuits of the control system are opened and operation of the machineis completely terminated. The opening of the switch 26 disconnects theheater circuit and the opening of the switch 27 opens the drive motorcircuit, the relay holding circuit and the timer motor circuit.Ordinarily it may be desired to have a machine cool-down period justbefore the operation is terminated, and in that case the cams 24 and 25may be so arranged that the switch 26 is opened slightly before theswitch 27. This will allow the dryer to operate without the heater beingenergized for a brief period before the dryer is completely shut off,thereby to allow it to cool down to a suitable temperature for theremoval of the clothes.

However, for the particular example here involved let it be assumed thatthe clothes are completely dried before the timer mechanism times themachine out. In such case the thermostat 30 will open. This breaks therelay holding circuit and allows the relay armature 34 to drop out. Inother words it allows the relay to open all of switches 35, 36 and 37.The opening of the contacts 35 opens the heater circuit whereby the airpassed to the drum is no longer heated. The opening of the switches 36and 37 likewise opens a point in the drive motor and timer circuits butas a result of the above-mentioned thermostat 31, the opening of theseswitches does not actually break the drive motor and timer circuits.Rather these circuits are still energized through the thermostat 31. Thethermostat 31 closed when the dryer exhaust temperature rose above thedesirable temperature for removing clothes from the machine, and theclosing of the thermostat 31 completes an alternate circuit forenergizing the drive motor and the thermostat.

Starting with the neutral line 59, this alternate circuit extendsthrough fusible link 60, conductor 61, timer operated switch 27 andconductors 62 and to the thermostat 31 itself. The other side of thethermostat is connected directly to the conductor 73 and from there thedrive motor and timer motor circuits are completed to the neutral line58 in the manner described above. The thermostat 31 thus provides acircuit in parallel with the switches 36, 37 of the relay for energizingthe drive motor and the timer motor when those switches are opened afterthe clothes have dried. The thermostat 31 remains closed to keep thedrive motor and timer motor in operation until such time as the exhausttemperature drops to a point at which the clothes may be advantageouslyremoved from the drum without any discomfort to the operator. When thedryer temperature reaches that point the thermostat 31 opens and that ofcourse breaks the drive motor and timer motor circuits. The operation ofthe machine is then completely terminated with all the elements thereofbeing de-energized.

If it were desired to have the dryer operate on high heat rather than oncontrolled heat, the only difference in the control setting would bethat the push button 42 would be pushed inwardly rather than the button43. The movement of the button 42 inwardly closes the switch 39 and thusprovides a shunt around the cycling thermostat 40. Thus when the dryergoes into operation as a result of the depressing of the start button55, the heater 17 is energized continuously rather than being cycled onand off. As a result the temperature of the inlet air entering the drumwill rise above the temperature held during the controlled heatoperation and the clothes will dry more quickly. This high heatoperation is generally more advantageous for loads of heavy fabrics andarticles such as shag rugs, dungarees, etc. The operation will beterminated in the same manner as the controlled heat operation either bythe sequential. opening of the exhaust thermostats 30 and 31 when theclothes have completely dried or else by the timer mechanism timing themachine out and opening the switches 26 and 27.

If it is desired to tumble clothes without the application of heat forsprinkling or other purposes, then the push button 41 is operated beforethe start button :35 is depressed. In that case the switch 38 is openedwhereby the eater circuit still remains open after the relay 32 closes.The same timer motor, drive motor and relay holding circuits arecompleted as before so that the drive motor and the timer motor run thesame as in the clothes drying operations. The only dilierence is that noheat is supplied to the clothes due to the break in the heater circuit.Since there is no heat applied to the clothes the exhaust thermostat 30will never open and therefore the sprinkling operation is alwaysterminated by the opening of the switches 26 and 27 by the timermechanism. The length of time that the clothes will be tumbled and/ orsprinkled depends upon the original setting of the dial 28. If it isdesired to sprinkle the clothes as well as tumble them, a suitablesprinkling container is, of course, placed within the drum 2.

With regard to both the controlled heat and the high heat clothes dryingoperations, both of them may be used to dry clothes completely in themanner described above. However, in addition they may be also used todamp dry clothes. In order to damp dry clothes the dial 28 is set atsome point between the dry sector and the otf sector. In other words itis set at a position within the portion of the dial which is numbered inFig. 2. With the dial set in such a position the timer mechanismordinarily times the machine out by opening switches 26 and 27 beforethe exhaust temperature rises far enough to open the thermostat 30. Thusthe machine will be turned off before the clothes are fully dried or inother words when they are still only damp dried. By pushing button 43during this damp dry operation the temperature of the inlet air will becontrolled by the thermostat 40. However if the button 42 is depressedthe heater 17 will be energized continuously.

Referring now to the door switch 74, this switch provides a safetyfeature during the operation of the machine. If the door 6 is opened atany time during the operation of the machine, the switch arm moves fromthe contact 75 to the contact 76. By this action both the drive motorand the timer motor circuits are broken. With the drive motor circuitbroken, the drive motor stops rotating the tumbling drum and the blower.Also, since the stopping of the drive motor results in the opening ofthe contacts 92 of the centrifugal switch, the heater circuit isdeenergized too. Thus the heater 17 also ceases operation until suchtime as when the door is reclosed. This stopping of the drum rotationand de-energizing of the heater provides for operator safety as well asallowing for the insertion and removal of articles from the drum. Thede-energization of the timer motor concurrently with the drive motor andthe heater when the door is opened prevents the opening of the door fromshortening the total time that the dryer is in operation. This controlof the timer motor results in the timer mechanism counting only the timethe dryer is actually in operation with the drum rotating, and not theshut-down time while the door is open.

In my improved control circuit the opening of the door does not,however, break the relay holding circuit. Rather the relay holdingcircuit remains energized even with the door opened so that the relayremains closed. Thus when the door is reclosed, the dryer will resumeoperation. When the door is opened, the relay holding circuit isenergized through the back contact 76 of the door switch. The relayspecifically is energized through the following circuit between neutralline 59 and supply conductor 58. Commencing with the neutral line 59 thecircuit extends through the fusible link 60 and a connector 96 to theback contact 76 of the door switch. From contact 76 it passes throughthe switch arm, and conductors 73 and 72 to switch 37 of the relay, andfrom there continues through conductor 70, thermostat 3t and conductors71 and 65 to the relay coil itself. The circuit is completed from therelay coil through conductors 66, 6'7 and 68 to the supply conductor 58.If the thermostat 31 has closed before the door 6 is opened, the relayholding circuit is also energized through it. But even if the thermostat31 is not closed, the relay holding circuit will be energized throughthe above-described circuit whenever the door is opened. Thus the relaycannot drop out and the dryer operation will be resumed when the door isclosed.

Besides those components already mentioned, my new and improved controlalso includes a light 97 for illuminating the interior of the dryer andan OZOne lamp 9% for freshening the air within the dryer. The lamps 97and 98 are so connected that they are energized whenever the door isopened and also whenever the machine is in operation. In both cases theyare energized between the neutral line 59 and the conductor 58. When thedoor is open, they are energized as follows. Commencing with the neutralline 59 the circuit extends through fusible link 60, conductor 96, theback contact 76 of the door switch, the door switch itself and aconductor 99 to the lamps. The lamps 97 and 8 are connected in seriesand the circuit is completed from them through a conductor 100 to thesupply conductor 58. When the machine is in operation and the door isclosed, the lamps 97 and 98 are energized through an alternate circuitcommencing with the neutral line 59 and extending through the fusiblelink 60, conductor 61, timer operated switch 27 and conductors 62 and 69to relay switches 36 and 37. From the relay switches the circuit passesthrough conductors 72, 73 and 39 to the lamps themselves and thence iscompleted and $9 to the lamps themselves and thence is completed tosupply conductor 58 through the conductor 100. Connectcd in thesecircuits the lamps are thus energized whenever the door is opened orwhenever the machine is in operation. Incidentally it will also be notedthat whenever the thermostat 31 is closed, they are also energizedthrough an alternate circuit through it. Thus they remain lit during thecool-down period of the machine following the drop-out of the relay 32.

From the above, it will be seen that l have provided a new and improvedcontrol system for a dryer which is effective to produce three differentoperations of the dryer. It provides a controlled heat clothes dryingoperation wherein the inlet air to the clothes tumbling drum is alwayskept at a safe temperature for even the sheerest of fabrics. It alsoprovides for a high heat operation wherein the dryer heater is energizedcontinuously. Further it provides a clothes tumbling or sprinklingoperation wherein the tumbling drum is rotated without the applicationof heat. The control is adjusted between the various operations merelyby the selective operation of a plurality of push-buttons. In both theclothes drying operations the control turns the dryer off automaticallywhen the clothes have fully dried. In the clothes sprinkling operationthe dryer may be set to run for any desired length of time, and in caseit is desired to damp dry clothes the dryer may be set to run for apredetermined length of time also in both the clothes drying operations.If the dryer door should be opened in any of the operations, thetumbling drum and the heater are turned off thereby to provide operatorsafety. However, the relay of the control is not de-energized wherebythe dryer is automatically placed back in operation when the door isreclosed without any further operation by the operator being required.

While in accordance with the patent statutes I have described what atpresent is considered to be the preferred embodiment of my invention, itwill be obvious to those skilled in the art that various changes andmodifications may be made therein without departing from the invention,and I, therefore, aim in the appended claims to cover all such changesand modifications as fall within the true spirit and scope of myinvention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a clothes dryer; clothes tumbling means; a drive motor for drivingsaid clothes tumbling means; a heater for heating the clothes beingtumbled; and control means for controlling said motor and said heater toproduce selectively a controlled heat clothes drying operation, a highheat clothes drying operation, and a clothes tumbling operation withoutheat, said control means comprising a timer mechanism including aplurality of timer operated switches; a motor circuit including one ofsaid timer operated switches; and a heater circuit, said heater circuitincluding another of said timer operated switches, a heater cyclingthermostat for cycling said heater, thereby to produce said controlledheat clothes drying operation, a normally open manually operable shuntswitch con nected in parallel circuit relation with the contacts of saidthermostat for shunting said thermostat, thereby to operate said heatercontinuously for said high heat clothes drying operation, and a normallyclosed manually operated heater switch arranged for de-energizing said13 heater thereby to produce said clothes tumbling operation withoutheat.

2. In a clothes dryer; clothes tumbling means; a drive motor for drivingsaid clothes tumbling means; a heater for heating the clothes beingtumbled; and control means for controlling said motor and said heater toproduce selectively a controlled heat clothes drying operation, a highheat clothes drying operation and a clothes tumbling operation withoutheat, said control means comprising a timer mechanism including aplurality of timer operated switches; a motor circuit including one ofsaid timer operated switches; a heater circuit, said heater circuitincluding another of said timer operated switches, a heater cyclingthermostat for cycling said heater, thereby to produce said controlledheat drying operation, a normally open manually operated shunt switchconnected in parallel circuit relation with the contacts of saidthermostat for shunting said thermostat, thereby to operate said heatercontinuously for said high heat drying operation, and a normally closedmanually operated heater switch arranged for deenergizing said heater,thereby to produce said clothes tumbling operation without heat; aplurality of push buttons for operating said heater switch and saidshunt switch; and linkage means interconnecting said push buttonswhereby operation of one of said heater and shunt switches from itsnormal position returns the other of said switches to its normalposition, with one of said push buttons being eifective to return bothof said switches to their normal positions simultaneously.

3. In a clothes dryer; an electrical heater, clothes tumbling means; adrive motor for driving said clothes tumbling means; means for blowingair over said heater and through said clothes tumbling means; andcontrol means for controlling said motor and said heater to produceselectively a controlled heat clothes drying operation, a high heatclothes drying operation and a clothes tumbling operation without heat,said control means comprising a timer mechanism including a plurality oftimer operated switches; a motor circuit including one of said timeroperated switches; a heater circuit, said heater circuit includinganother of said timer operated switches, a heater cycling thermostatresponsive to the temperature of the inlet air entering said clothestumbling means from said heater for cycling said heater, thereby toprovide said controlled heat clothes drying operation, a normally openmanually operated switch connected in parallel circuit relation with thecontacts of said thermostat for shunting said thermostat, thereby tooperate said heater continuously for said high heat clothes dryingoperation, a normally closed manually operated heater switch arrangedfor de-energizing said heater, thereby to produce said clothes tumblingoperation without heat, and means including thermostatic meansresponsive to the temperature of the exhaust air leaving said clothestumbling means for opening said heater circuit and said motor circuitindependently of said timer operated switches when said clothes arefully dried in both said high heat clothes drying operation and saidcontrolled heat clothes drying operation.

4. In a clothes dryer; an electrical heater; clothes tumbling means; adrive motor for driving said clothes tumbling means; means for blowingair over said heater and through said clothes tumbling means; andcontrol means for controlling said motor and said heater to produceselectively a controlled heat clothes drying operation, a high heatclothes drying operation, and a clothes tumbling operation without heat,said control means comprising a timer mechanism including a plurality oftimer operated switches; a motor circuit including one of said timeroperated switches; and a heater circuit, said heater circuit includinganother of said timer operated switches, a heater cycling thermostatresponsive to the temperature of the inlet air entering said clothestumbling means from said heater for cycling said heater, thereby toprovide said controlled heat clothes drying operation, a normally openmanually operated switch connected in parallel circuit relation with thecontacts of said thermostat for shunting said thermostat, thereby tooperate said heater continuously for said high heat clothes dryingoperation, and a normally closed manually operated heater switcharranged for de-energizing said heater, thereby to produce said clothestumbling operation without heat; and means including a pair ofthermostats responsive to the temperature of the exhaust air leavingsaid clothes tumbling means for opening first said heater circuit andthen said motor circuit independently of said timer operated switcheswhen said clothes are fully dried in both said high seat clothes dryingoperation and said controlled heat clothes drying operation.

5. In a clothes dryer; an electrical heater; clothes tumbling means; adrive motor for driving said clothes tumbling means; means for blowingair over said heater and through said clothes tumbling means; andcontrol means for controlling said motor and said heater to produceselectively a controlled heat clothes drying operation, a high heatclothes drying operation and a clothes tumbling operation without heat,said control means comprising a timer mechanism including a plurality oftimer operated switches; a motor circuit including one of said timeroperated switches; and a heater circuit, said heater circuit includinganother of said timer operated switches, a heater cycling thermostatresponsive to the temperature of the inlet air entering said clothestumbling means from said heater for cycling said heater, thereby toprovide said controlled heat clothes drying operation, a normally openmanually operated switch connected in parallel circuit relation with thecontacts of said thermostat for shunting said thermostat, thereby tooperate said heater continuously for said high heat clothes dryingoperation, and a normally closed manually operated heater switchconnected in series with said thermostat for sle-energizing said heater,thereby to produce said clothes tumbling operation without heat, andmeans including a relay having contacts in both of said motor and heatercircuits and a pair of thermostats responsive to the temperature of theexhaust air leaving said clothes tumbling means for opening first saidheater circuit and then said motor circuit independently of said timeroperated switches when said clothes are fully dried in both said highheat clothes drying operation and said controlled heat clothes dryingoperation, one of said exhaust air thermostats de-energizing said relayat a pre-determined high temperature of said exhaust air to open therelay contacts in both of said circuits, and the other of said exhaustair thermostats being connected across the contacts of said relay insaid motor circuit and shunting said contacts to continue said motorcircuit energized until the dryer temperature has dropped to a suitablelevel for the removal of the clothes.

6. The combination of claim 5 including a plurality of push buttons foroperating said manually operated heater and shunt switches, and linkagemeans interconnecting said push buttons whereby operation of one of saidswitches from its normal position turns the other of said switches toits normal position, with one of said push buttons being eifective toreturn both of said switches to their normal positions simultaneously.

7. In a clothes dryer; an electrical heater; clothes tumbling means; adrive motor for driving said clothes tumbling means; means for blowingair over said heater and through said clothes tumbling means; andcontrol means for controlling said motor and said heater to produceselectively a controlled heat clothes drying operation, a high heatclothes drying operation and a clothes tumbling operation without heat,said control means comprising a timer mechanism including a plurality oftimer operated switches; a motor circuit including one of said timeroperated switches; and a heater circuit, said heater circuit including asecond of said timer operated switches, a heater cycling thermostatresponsive to the temperature of the inlet air entering said clothestumbling means from said heater for cycling said heater, thereby toprovide said controlled heat drying operation, a normally open manuallyoperated switch connected in parallel circuit relation with the contactsof said thermostat for shunting said thermostat, thereby to operate saidheater continuously for said high heat clothes drying operation, and anormally closed manually operated heater switch connected in series withsaid thermostat for de-energizing said heater, thereby to produce saidclothes tumbling operation without heat; and means including a relay anda pair of thermostats responsive to the temperature of the exhaust airleaving said clothes tumbling means for opening first said heatercircuit and then said motor circuit independently of said timer operatedswitches when said clothes are fully dried in both said high heatclothes drying operation and said controlled heat clothes dryingoperation, said relay having contacts in both said motor circuit andsaid heater circuit, and an operating coil for closing said contacts,one of said thermostats de-energizing said coil when said clothes havedried and the other of said thermostat shunting the relay contacts insaid motor circuit to produce a cool down period; and safety switchmeans including a door switch for opening said motor circuit and saidheater circuit whenever said door is opened, with said relay coil beingenergized independently of said motor circuit whereby the relay circuitis not de-energized by the opening of said door but is de-energized onlyby the opening of said one exhaust thermostat or by the opening of oneof the timer operated switches.

8. In a clothes dryer; clothes tumbling means; a drive motor for drivingsaid clothes tumbling means; an electrical heater; means for blowing airover said heater and through said clothes tumbling means; and controlmeans for said heater and said motor comprising a timer mechanismincluding a plurality of timer operated switches, a relay having aplurality of sets of contacts and a coil for controlling said contacts,a heater circuit including a first of the timer operated switches and afirst set of the relay contacts, a drive motor circuit including asecond of the timer operated switches and a second set of the relaycontacts, a relay circuit for energizing said relay coil including oneof the timer operated switches and one set of the relay contacts, athermostat responsive to the temperature of the exhaust air leaving saidtumbling means for breaking said relay circuit when the exhaust airreaches a predetermined high temperature, thereby to tie-energize saidcoil and open said relay contacts, safety switch means including a doorswitch for opening said motor circuit and said heater circuit wheneverthe dryer door is opened, with said relay circuit being energizedindependently of said motor circuit whereby said relay circuit is notdeenergized by the opening of said door but is de-energized only by theopening of said thermostat or by the opening of said one of the timeroperated switches.

9. Combination of claim 8 including a manually operated normally openswitch connected in parallel with said one set of relay contacts forinitially energizing said relay coil to place said dryer in operation.

10. In a clothes dryer; an electrical heater; clothes tumbling means; adrive motor for driving said clothes tumbling means; means for blowingair over said heater and through said clothes tumbling means; andcontrol means for said heater and said motor comprising a timermechanism including a plurality of timer operated switches, a relayhaving a plurality of sets of contacts and a coil for controlling saidcontacts, a heater circuit including a first of the timer operatedswitches and a first set of said relay contacts, a drive motor circuitincluding a second of said timer operated switches and a second set ofsaid relay contacts, a relay circuit for energizing said relay coilincluding one of said timer operated switches and one set of said relaycontacts, a first thermostat responsive to the temperature of theexhaust air leaving said tumbling means for breaking said relay circuitwhen said exhaust air reaches a predetermined high temperature, therebyto open said relay contacts and deenergize said heater and relaycircuits, a second thermostat having contacts connected in parallel withsaid second set of relay contacts in said motor circuit, said secondthermostat being also responsive to the temperature of said exhaust airand closing its contacts so long as said exhaust air temperature isabove a predetermined lower temperature suitable for the removal ofclothes from said tumbling means, whereby said motor circuit is notbroken with said heater circuit when said relay coil is de-energized butremains energized until said exhaust temperature decreases to said lowervalue or until said second switch of said timer mechanism is opened, andsafety means for opening said motor circuit and said heater circuit whenthe door of said dryer is opened, said safety means comprising a doorswitch for opening said motor circuit, and a motor centrifugal switchfor opening said heater circuit when said motor ceases operation, withsaid relay circuit being energized through a back contact of said doorswitch when said door is open, whereby said relay circuit is notde-energized by the opening of said door.

11. In a clothes dryer; an electrical heater; clothes tumbling means; adrive motor for driving said clothes tumbling means; means for blowingair over said heater and through said clothes tumbling means; andcontrol means for said heater and said motor comprising a timermechanism including a plurality of timer operated switches, a relayhaving a plurality of sets of contacts and a coil for operating saidcontacts, a heater circuit including a first of said timer operatedswitches and a first set of relay contacts, a drive motor circuitincluding a second of said timer operated switches and a second set ofsaid relay contacts, a relay circuit for energizing said relay coilincluding one of said timer operated switches and one set of said relaycontacts, a thermostat responsive to the temperature of the exhaust airleaving said tumbling drum for breaking said relay circuit when saidexhaust air reaches a predetermined high temperature, thereby tode-energize said coil and open said relay contacts, and a manuallyoperated normally open switch connected in parallel with said one set ofrelay contacts for initially energizing said relay coil to place saiddryer in operation.

12. In a clothes dryer; an electrical heater; clothes tumbling means; adrive motor for driving said clothes tumbling means; means for blowingair over said heater and through said clothes tumbling means; andcontrol means for controlling said motor and said heater to produceselectively a controlled heat drying operation, and a high heat clothesdrying operation, said control means comprising a timer mechanismincluding a plurality of timer operated switches; a motor circuitincluding one of said timer operated switches; and a heater circuit,said heater circuit including another of said timer operated switches, aheater cycling thermostat responsive to the temperature of the inlet airentering said clothes tumbling means from said heater for cycling saidheater, thereby to provide said controlled heat drying operation, and anormally open manually operated switch connected in parallel circuitrelation with the contacts of said thermostat for shunting saidthermostat, thereby to operate said heater continuously for said highheat drying operation; and means including a thermostat responsive tothe temperature of the exhaust air leaving said clothes tumbling meansfor opening said heater circuit and said motor circuit independently ofsaid timer operated switches when said clothes are fully dried in bothsaid high heat clothes drying operation and said controlled heat clothesdrying operation.

137 In a clothes dryer; clothes tumbling means; a drive motor fordriving said clothes tumbling means; an electrical heater; means forblowing air over said heater and through said clothes tumbling means;and control means for said heater and said motor comprising a relayhaving a plurality of sets of contacts and a coil for controlling 17said contacts, a heater circuit including said heater and a first set ofthe relay contacts, a drive motor circuit including said drive motor anda second set of the relay contacts, a relay circuit for energizing saidrelay coil including one set of the relay contacts, a thermostatresponsive to the temperature of the exhaust air leaving said tumblingmeans for opening said relay circuit when the exhaust air reaches apredetermined high temperature, thereby to de-energize the coil and opensaid relay contacts to terminate the dryer operation, and safety switchmeans including a door switch for opening said motor circuit and saidheater circuit whenever the dryer door is opened, with said relaycircuit being energized independently of said motor circuit whereby saidrelay circuit is not de-energized by the opening of said door but isdeenergized only by the opening of said thermostat.

References Cited in the file of this patent UNITED STATES PATENTS2,505,041 Gorsuch Apr. 25, 1950 10 2,654,160 Peterson Oct. 6, 19532,707,837 Robinson et a1 May 10, 1955

